Expansion joint



A. CqFlSCHER EXPANSION JOINT Filed March 7, 1959 April 13, 1943.

April 13, 1 Ab. FISCHER EXPANS ION JOINT Filed March 7, 1939 2 Sheets-Sheet 2 l 40 MI Patented Apr. 13, 1943 2,316,233. nxmnsfim JOINT Albert 0. Fischer, Chicago, Ill.

Application March 7, 1939, Serial No. 280,444

8 Claims.

The present invention relates to a structural assembly composed of two juxtaposed structural elements provided with a spacing joint therebetween, and more particularly to an expansion joint between pavement slabs which is designed to maintain its integrity over a long period of time.

The present invention proceeds upon the principle of the provision .of an expansion joint of plastic material subject to cold flow and deformation which is disposed between two structural slabs such as pavement sections, and which is subjected to repeated compressive stresses arising from the expansion of the slabs giving rise to a tendency to force the plastic filler material from between the slabs, which is needed to fill the space therebetween when the parts return to their original positions upon the contraction of the slabs. The present invention makes provision for the accommodation of the plastic material in chambers formed at the ends of the slabs for receiving the material which would normally be extruded from the joint, and furthermore provides for the exertion of proper forces acting in the proper directions upon the return of the slabs to their normal positions occasioned by the contraction thereof to force the material of the expansion joint back .into the original position, whereby foreign matter such as water 'and sand are incapable of entering into the Joint and disintegrating the same within a comparatively short period of time.

Whereas the control of the expansion joint material in response to the expansive movements of the structural slabs has been a relatively simple matter, the provision of positively acting forces brought into operation upon the contrac-' tion of the slabs has presented previously insurmountable problems which the present invention seeks to solve. The forces coming into play upon the contraction of the. slabs. may be provided extraneously, for example, by springs which are permitted to come into action upon the contraction of the slabs, or the movements of the slabs themselves in the course of the contraction may be employed toproduce the desired forces in directing the material into the proper locations.

It is the object of the present invention to provide expansion joints between structural elements possessing the above capabilities of controlling the plastic flow of the joint material in accordance with the different forces imposed thereupon at different timesiby the expansive and contractile. movements of the slabs.

It is a further object of the invention to provide an expansion joint assembly which is economical and rugged, and which operates as a reinforcement for the structural slabs at their weakest points, namely, at the joints therebetween.

Other objects and purposes will appear from the more detailed description of the invention described hereinafter taken in conjunction with the accompanying drawings, wherein:

Figure 1 shows a vertical sectional view of an expansion joint in accordance with the present invention; V

Figure 2 is a. horizontal sectional view alon line 2-4 of Figure 1;

Figures 3, 4 and 5 are perspective views of different forms of the channel members for defining the chambers for accommodating the compressed plastic Joint material during the expanded conditions of the structural slabs;

Figure 6 is a vertical sectional view of a diflerent embodiment of the invention; and,

Figure 7 is a horizontal sectional view of the expansion Joint shown in Figure 6.

In Figure l are shown adjoining structural slabs l and 2 which for the sake of illustration have been shown as pavement slabs which may be provided with surfacing layers l and 2' sepa ated by a crown portion 3 ,of rubber or other plastic material disposed upon a metallic channel member 4 which is of irregular configuration in order to permit the movement of the parts.

A plastic filler medium 13, subject to deformation and cold flow. is disposed in the joint between the slabs I and 2, and in the normal expansion of the slabs, the tendency arises for the plastic medium I! to be forced from the space between the slabs. Thus, without the provision of the crown channel 14 and the crown filler 3, such material is forced over the surface of the roadway, and upon the return of the slabs, the material is no longer available for eifectuating a complete filling of the space between the slabs whereupon surface waters and sand enter into the joint and eventually undermine the same to cause damage to the roadway. The channel 4 and the plastic crown tiller 3 are insuflicient'to counteract the tendency of the plastic filler I 3 to be forced from the joint and eventually these barriers give way so that a carefully constructed roadway soon deteriorates despite the adoption of such refinements.

nels extending across the complete width of the roadway. In the embodiment shown in Figure 2, the channels I and 8 are shown extending across the roadway. Thimbles or sleeves 5 are disposed in recesses along spaced points of the roadway. These thimbles are formed of any suitable material such as metal, fiber, cardboard or the like which is adequate to permit the concrete slabs to be cast therearound in order to form cavities or recesses for accommodating dowel bars 6 embedded in the opposing slab in alignment with the thimbles 5. The dowels and sleeves are staggered with respect to each other in the opposite slabs.

Within the chambers formed by the channels 1 and 8 are disposed pressing plates II and I2 which are loosely fitted over the dowel bars 6 and are designed to be maintained in close engagement with the opposite faces of the expansion joint material by the action of coiled springs I6 and I I, also mounted loosely on the dowel bars.

When the slabs I and 2 expand they exert a compressive force upon the joint material outside of the channels] and 8 which is not experienced by the joint material on the inside of the channels I and 8. Within these channels, the movement of the slabs merely causes a movement of the dowel bars 6 within the thimbles or sleeves 5. The material compressed above and below the channels I and 8 in Figure 1 tends to bulge into the chambers within the channels I and B to cause a separating movement of the pressing plates II and I2 which in turn serves to compress the springs i6 and I1, storing up energy therein. When the slabs I and 2 return to their original positions, the force stored in springs l6 and I1 is exerted upon the plates II and I2 to force the material of the expansion joint at this point to the spaces outside of the chambers I and 8 to thereby return the expansion joint to its original state. The space formed below the crown 4 operates as reserve storage for the material extruded in the upper portion of the joint. Thereby a tight joint is maintained at all times despite repeated expansions and contractions of the structural slabs.

Figures 3, 4 and 5 show difierent forms which the channel members 1 and 8 may assume, A, B and C, respectively, to form the chambers for accommodating the bulged expansion joint material. These are shown with apertures l8 therein for accommodating the dowels 6 extending therethrough.

In Figures 6 and 7 is illustrated another embodiment of the invention wherein no extraneous force-producing means such as springs are utilized, but the return movements of the concrete slabs are used for returning the plastic filler with the channels into the joint outside of the chambers. In this construction, the chambers onthe opposite sides of the plastic joint are defined by channels 31 and 38 around which the concrete slabs are cast. A plurality of dowel bars 39 are mounted in the slab I and may be retained securely therein by grooves 44 in the dowel bars. Sleeves 40 are disposed opposite the dowel bars 39 in the concrete slab 2 and are likewise retained securely therein by grooves 44. Alternately disposed with respect to dowel bars 39 and sleeves 40 and operating in opposite relationship are dowel bars 49 set in concrete slab 2 cooperating with sleeves 50 in concrete slab I. This arrangement'of parts is clearly illustrated in Figure 7 showing a plan View of the joint assembly. Each of the sleeves extends through the channel in the slab in which the sar e is mounted, through the chamber defined by the channel, a pressing plate disposed within the channel and adjacent the expansion joint filler, the expansion joint fil er,

and through the pressing plate on the opposite side of the filler at which point it is joined to this pressing plate. Thus, with the pressing plates 4| and 42 disposed within the channels 31 and 38, the sleeves 40 are rigidly joined to the pressing plate 4| while the sleeves 50 arerigidly joined to the pressing plate 42. This joint may be obtained by an upsetting or crimping operation.

The assembly illustrated in Figures 6 and 7 operates in the following manner. Upon the expansion of the concrete slabs the tendency exists for the pressing plate 4| to be forced to the right by the expansion of the slab 2 and for the pressing plate 42 to be moved to the left by the expansion of the slab I'in view of the rigid connection between these respective pressing plates and the sleeves rigidly mounted in these slabs. Thereupon the filler is permitted to bulge within the chambers defined by the channels 31 and 38 in consequence of the compressing action imposed upon the filler outside of the channels, namely, above'and below the same. On the other hand, upon a contraction of the slabs, slab 2 serves to move pressing plate 4| to the left to return the plastic material into the joint outside of the chambers while the contraction of the slab serves to move the pressing plate 42 to the right to exert a pressing action upon the plastic medium in the chambers in the opposite direction from the plate I, thereby effectively extrud- I ing the material back into its normal place. It is noted that in this embodiment of the invention, the dowel bars serve primarily as guiding means for the sleeves which, by virtue of their connection to the pressing plates 4| and 42, exert the primary forces for directing the material back into the joint space. However, these dowel bars serve as effective transloading elements for reenforcing the roadwai construction at the joints.

In this embodiment of the invention, the crown 4 and the crown filler 3 may be incorporated as in the case of the embodiment shown in Figures 1 and 2. Also the slab sections may be provided with surfacing layers if such are desired. On the other hand the slabs may be formed as single cast blocks in a manner well known in the art. The plastic filler I3 may be made of any premolded flowable expansion joint material also well known in the art.

While I have described my invention as embodied in specific form and as operating in a specific manner for purposes of illustration, it

should be understood that I do not limit my invention thereto, since various modifications will suggest themselves to those skilled in the art without departing from the spirit of my invention, the scope of which is set forth in the annexed claims.

What I claim is:

1. A paving assembly comprising two spaced paving sections, a plastic filler subject to deformation and cold flow between said sections, channel members within said paving sections defining empty chambers adjacent to said filler upon the opposite sides thereof, a pressing plate in each of said chambers and mechanically operating means connected therebetween and said paving sections for pressing the filler material bulged thereat in said chambers by the expansion of the paving sections to the portions thereof outside of said channel members upon the contraction of said paving sections.

2. A paving assembly comprising two spaced paving sections, a plastic filler subject to defortion, pressing plates loosely mounted on said dowel bars adjacent to said plastic filler, and spring means between said pressing plates and said channel walls for storing the energy of compression of the filler outside of said chambers upon the expansion of said paving sections for return to the filler inside of said chambers by said spring means and the consequent restoration of the filler outside of said chambers to its normal state as permitted by the contraction of said paving sections.

3. A paving assembly comprising two spaced paving sections, a plastic filler subject to deformation and cold fiow between said sections, channel members within said paving sections defining void chambers adjacent to said filler upon the opposite sides thereof, a plurality of dowel bars fixedly mounted. in one of said paving sections and loosely guided in the other paving section, a plurality of dowel bars alternately disposed with respect to said first group of bars and fixedly mounted in said last-mentioned paving section and loosely guided in.said one paving section,

pressing plates -loosely mounted on said dowel bars adjacent to said plastic filler, and spring means between said pressing plates and said channel walls for storing the energy of compression occasioned by the expansion of said paving sections and the extrusion of said filler into said chambers and for restoring said filler upon the contraction of said paving sections.

4. A paving assembly comprising two spaced paving sections, a plastic filler subject to deformation and cold flow between said sections, channel members within said paving sections defining void chambers adjacent to said filler upon the opposite sides thereof, a plurality of dowel bars fixedly mounted in one of said paving sections and loosely guided in the other paving section, a plurality of dowel bars alternately disbers adjacent to said plastic filler, a sleeve fixedly mounted in one of said paving sections and connected with the pressing plate remote therefrom, a sleeve fixedly mounted in the other one of said paving sections and connected with the pressing plate remote therefrom, and dowel bars in alignment with said sleeves and mounted in the opposite respective paving sections for guiding the movements of said sleeves.

6. A paving assembly comprising two spaced paving sections, a plastic filler in the form of an integral mass subject to deformation and cold fiow between said sections, channel members within said paving sections defining void chambers adjacent to said filler upon the opposite sides thereof, a pressing plate in each of said chambers adjacentto said plastic filler, a plurality of sleeves fixedly mounted in one of said paving sections and connected with the pressing plate remote therefrom, a plurality of sleeves alternating with said first group of sleves and fixedly mounted in the other one of said paving sections and connected with the pressing plate remote therefrom, anddowel bars in alignment with said pressing plate thereat, through the plastic filler,

' and connected with the pressing plate on the opposed with respect to said first group "of bars and fixedly mounted in said last-mentionedvpaving section and loosely guided in said one paving section, pressing plates loosely mounted on said dowel bars adjacent to said plastic filler, and coiled springs mounted on said dowel bars between said pressing plates and said channel walls at the ends thereof fixedly mounted in said paving sections for storing the energy of compression integral mass subject to deformation and cold flow between said sections, channel members within said paving sections defining void chambers adjacent to said filler upon the opposite sides thereof, a pressing plate in each of said champosite side of the filler, a sleeve fixedly mounted in the other one of said paving sections extending through the channel member and the pressing plate thereat, the plastic filler, and connected \with the pressing plate remote therefrom, and dowel bars in alignment with said sleeves and mounted inthe opposite respective paving sections for guiding the movements of said sleeves.

8. A paving assembly comprising two spaced paving sections, a plastic filler in the form of an integral mass subject to deformation and cold flow between said sections, channel members within said paving sections defining void chambers adjacent to said filler upon the opposite sides thereof, a pressing plate in each of said chambers adjacent to said plastic filler, a plurality of sleeves fixedly mounted in one of said paving sections extending through the channel member and the pressing plate thereat, through the plastic filler, and connected with the pressing plate on the opposite side of the filler, a plurality of sleeves alternating with said first group of sleeves and 

